(707e) Research On H2S Removal and Oxidation From Acidic Gas with [Bmim]2BF4OH

Hydrogen sulfide (H₂S), which can cause catalyst poisoning and pipeline corrosion, is produced along with methane in natural gas fields, coal gas fields and crude oil fields. General absorbents of H₂S, such as MDEA, MEA, DGA, DIPA are volatile. In contrast ionic liquids (ILs) provides a vapourless, thermally stable, reusable ?green? solvent and catalyst for chemical reaction, so ILs has very possibility for removal of H₂S.

A stable, tack-specific ionic liquids, [bmIm]₂BF₄OH, has been used as a catalyst and as a reaction medium in oxidation of hydrogen sulfide (H₂S) to sulfur (S). Very interestingly, although other simple alkaline solvent such as aminoethyl alcohol (MEA), can absorb H₂S, not only can [bmIm]₂BF₄OH improve the absorption of H₂S, but also drive the oxidation of H₂S with oxygen to S exclusively, that is not reported before.

With the ¹H NMR spectra, IR spectra and MS spectra, we can conclude that [bmIm]₂BF₄OH with oxygen forms intermediate of ketone or aldehyde, then is reduced by H₂S, and finally is returned to the original state.

The significant advantages of this strategy are mild reaction conditions (room temperature) and high isolated yields of S (>90%). Because it can combine the absorption and the oxidation, [bmIm]₂BF₄OH shows great potential in green process engineering of oxidative desulphurization of natural gas, coal gas and so on.

Key words: H₂S, Ionic liquid, oxidative desulphurization, Catalysis

Acknowledgments

The authors sincerely appreciate financial supports from National Scientific Funding of China for Distinguished Young Scholar (20625618 and 20806083), National Basic Research Program of China (973 Program, 2009CB219902).

* Corresponding author. E-mail addresses: sjzhang@home.ipe.ac.cn